A216656 Number of n-digit 6th powers.

2, 1, 1, 1, 2, 3, 5, 7, 10, 15, 22, 31, 47, 69, 101, 148, 217, 318, 468, 687, 1008, 1479, 2171, 3187, 4678, 6867, 10078, 14793, 21714, 31870, 46780, 68664, 100784, 147931, 217134, 318707, 467800, 686635, 1007843, 1479311, 2171332, 3187079, 4677993, 6866354

Offset

1,1

Comments

a(6*k+1) + a(6*k+2) + a(6*k+3) + a(6*k+4) + a(6*k+5) + a(6*k+6) = 9*10^k for k >= 1. - Robert Israel, Jul 22 2018

Links

Alois P. Heinz, Table of n, a(n) for n = 1..1000

Example

a(1) = 2: 0, 1.
a(2) = 1: 64.
a(3) = 1: 729.
a(4) = 1: 4096.
a(5) = 2: 15625, 46656.
a(6) = 3: 117649, 262144, 531441.
a(7) = 5: 1000000, 1771561, 2985984, 4826809, 7529536.
a(8) = 7: 11390625, 16777216, 24137569, 34012224, 47045881, 64000000, 85766121.

Maple

r:= proc(n, k) local b; b:= iroot(n, k); b+`if`(b^k<n, 1, 0) end:
a:= n-> r(10^n, 6) -r(10^(n-1), 6) +`if`(n=1, 1, 0):
seq(a(n), n=1..50);

Crossrefs

Column k=6 of A216653.

Sequence in context: A134132 A308121 A030424 * A353435 A295679 A287214

Adjacent sequences: A216653 A216654 A216655 * A216657 A216658 A216659

Keyword

nonn,base

Author

Alois P. Heinz, Sep 12 2012

Status

approved